Video cameras that employ a disk-shaped recording medium as a storage medium have started to become commercially available in recent years. Such video cameras are compact and highly portable and it is believed that they will become increasingly popular forwarding the future. In such a device, a multiplexed stream is recorded on the recording medium at the time of recording. The multiplexed stream is the result of multiplexing a video stream, which has been compressed and encoded as by the MPEG scheme, and an audio stream.
The DVD-Video standard is known as a standard for thus recording video data and audio data on a recording medium. With the DVD-Video standard, moving picture data is recorded upon being encoded by the MPEG-2 scheme. According to the MPEG-2 standard, a buffer memory referred to as a VBV (Video Buffering Verifier) buffer for accumulating encoded data is hypothesized between an encoder and a decoder in a signal processing circuit, and encoding is performed in such a manner that the VBV buffer will not fail.
However, in a case where pictures shot by a video camera are recorded, recording is performed by so-called stop-and-go connective shooting. That is, intermittent recording that involves recording, temporary stop, recording, temporary stop, recording and so on, can be performed frequently. Imagine a case where video streams of a plurality of scenes encoded and recorded intermittently are connected and recorded in such a manner that there will be no loss of presentation at the time of playback. In this case, there is the danger that the VBV buffer will fail because the data of succeeding scene is input to the VBV buffer without taking into consideration the amount of the VBV buffer occupied by a preceding scene.
An example of a VBV buffer in the failed condition is underflow, namely when data that is to be decoded has not accumulated in memory at such time that the data is to be decoded.
Accordingly, as disclosed in the specification of Japanese Patent Laid-Open No. 2005-136633, there has been proposed a technique in which the amount of code of the lead-off picture in a succeeding chapter of a succeeding video stream is adjusted at the time of recording in order to perform recording connectively without VBV buffer failure and in such a manner that playback can be performed without loss of data between items of video data of a plurality of scenes.
With the prior-art arrangement disclosed in the specification of Japanese Patent Laid-Open No. 2005-136633, recording without loss of data at the time of playback is possible by controlling the fullness of the VBV buffer at the time of recording. However, the amount of code that can be allocated to the lead-off picture of a succeeding video stream depends upon the amount of the VBV buffer occupied by a preceding video stream at the time that playback of the succeeding video stream starts. Consequently, if a situation arises in which a sufficient amount of code cannot be allocated to the lead-off picture of the succeeding video stream at the time of playback, the image quality of playback video may be degraded by loss of data during the course of changeover from the preceding stream to the succeeding stream, and there is the possibility that the user will find this annoying.